Originally Posted by
FBinNY
As Hillrider said, there has only been one standard in use throughout the world (except France (figures)) for many decades.
No, there was an Italian pedal thread. It's, in true insane italian fashion, 9/16" X 20 tpi, with, like you'd expect, Whitworth thread form. 55 degrees, rounded roots and crests, instead of the 60 degree thread that everyone else used. A tap, or just a bunch of force, will get them to take a standard pedal.
OP: examine your original pedals; if they're Italian threaded, there's a good chance they'll say "D" on the right one, and "S" of the left.